1. Technical Field
This invention relates to fiber-forming melt-processible polyesters that exhibit optical anisotropy in the melt.
2. Background and Objects
Melt-processible, wholly aromatic polyesters which form optically anisotropic melt phases (AMP) are known in the art.
U.S. Pat. No. 4,318,842 discloses melt-processible AMP polyesters which can be prepared from 6-hydroxy-2-naphthoic acid (20-90 mol %), 1,4-cyclohexanedicarboxylic acid (5-40 mol %), an aromatic diol HO-Ar-OH (10-40 mol %) and an aromatic diacid HO.sub.2 C-Ar-CO.sub.2 H (10-40 mol %). AMP polyesters are also disclosed in U.S. Pat. No. 4,219,461; these can be prepared from 6-hydroxy-2-naphthoic acid (20-40 mol %), 4-hydroxybenzoic acid (10-50 mol %), an aromatic diol (5-30 mol %), and an aromatic diacid (5-30 mol %). U.S. Pat. No. 4,318,841 discloses melt-processible AMP polyesters which can be prepared from 6-hydroxy-2-naphthoic acid (5-60 mol %), 4-hydroxybenzoic acid (5-70 mol %), terephthalic acid (10-45 mol %), and resorcinol (10-45 mol %). U.S. Pat. No. 4,256,624 discloses melt-processible AMP polyesters which can be prepared from 6-hydroxy-2-naphthoic acid (10-90 mol %), an aromatic diol HO-Ar-OH (5-45 mol %), and an aromatic diacid (5-45 mol %).
U.S. Pat. No. 4,269,965 discloses fiber-forming copolyesters which are melt-anisotropic and consist essentially of ##STR4## wherein X and R are independently H, CH.sub.3 or Cl. U.S. Pat. No. 4,232,143 discloses fiber-forming AMP polyesters consisting essentially of ##STR5## wherein X and R are independently H, CH.sub.3, or Cl. U.S. Pat. No. 4,245,082 discloses fiber-forming melt-anisotropic polyesters which consist essentially of substantially equimolar amounts of ##STR6## wherein R.sub.1 in at least 85 mol % of the dioxy units is ##STR7## wherein X is CH.sub.3 or Cl and n is 0, 1, or 2, and R.sub.2 in at least 85 mol % of the diacyl units is p-phenylene, 2,6-naphthylene, or p,p'-biphenylene.
U.S. Pat. No. 4,276,226 discloses diketodiols and diesters of the formula ##STR8## wherein R is independently methyl or chloro, R.sup.1 is independently hydrogen or R, R.sup.2 is 1,4-phenylene, 1,3-phenylene, 2,6-naphthylene, 4,4'-biphenylene, or 4,4'-biphenylene ether, and R.sup.3 is hydrogen or ##STR9## wherein R.sup.4 is a hydrocarbon group of 1-10 carbon atoms. Also disclosed is the reaction of the above with aromatic diacids to form melt-spinnable polyesters. U.S. Pat. No. 4,226,970 discloses melt-processible AMP polyesters, and high modulus filaments thereof, consisting essentially of ##STR10## wherein X is CH.sub.3 or Cl and Ar is 1,3- or 1,4-phenylene, and ##STR11## wherein R.sub.2 is selected from a variety of diradicals, including 1,4-phenylene.
It is an object of this invention to provide novel wholly aromatic polyesters. Another object is to provide such polyesters which form anisotropic melts and which are highly melt processible, for example, into shaped articles, including fibers and filaments, particularly the modulus of which can be increased by heat treatment. Other objects will become apparent hereinafter.